CN110095332B - Sealing method and sealing device for rock sample in triaxial Hopkinson pressure bar experiment - Google Patents
Sealing method and sealing device for rock sample in triaxial Hopkinson pressure bar experiment Download PDFInfo
- Publication number
- CN110095332B CN110095332B CN201910220522.5A CN201910220522A CN110095332B CN 110095332 B CN110095332 B CN 110095332B CN 201910220522 A CN201910220522 A CN 201910220522A CN 110095332 B CN110095332 B CN 110095332B
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- heat
- sealing
- rod
- rock sample
- shrinkage
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- 238000007789 sealing Methods 0.000 title claims abstract description 79
- 239000011435 rock Substances 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims abstract description 33
- 238000002474 experimental method Methods 0.000 title claims abstract description 27
- 238000012360 testing method Methods 0.000 claims abstract description 7
- 230000005540 biological transmission Effects 0.000 claims description 35
- 230000008602 contraction Effects 0.000 claims description 18
- 239000004831 Hot glue Substances 0.000 claims description 12
- 229910001220 stainless steel Inorganic materials 0.000 claims description 5
- 239000010935 stainless steel Substances 0.000 claims description 5
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 3
- 239000010963 304 stainless steel Substances 0.000 claims description 2
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 claims description 2
- 239000003292 glue Substances 0.000 claims description 2
- 229920000098 polyolefin Polymers 0.000 claims description 2
- 210000000867 larynx Anatomy 0.000 claims 3
- 206010043528 Throat tightness Diseases 0.000 claims 1
- 238000005253 cladding Methods 0.000 claims 1
- 239000000314 lubricant Substances 0.000 claims 1
- 230000003068 static effect Effects 0.000 abstract description 2
- 230000008569 process Effects 0.000 description 10
- 230000000694 effects Effects 0.000 description 5
- 238000010276 construction Methods 0.000 description 4
- 239000010720 hydraulic oil Substances 0.000 description 4
- 238000011160 research Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 239000005038 ethylene vinyl acetate Substances 0.000 description 2
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/36—Embedding or analogous mounting of samples
Abstract
The invention provides a device and a method for sealing a rock sample for a triaxial Hopkinson pressure bar experiment, which are mainly used for sealing a rock pattern arranged on a triaxial Hopkinson pressure bar experiment rock testing machine in a multi-layer manner by adopting a shrinkage sealing washer, a heat shrinkage pipe and a shrinkage hoop. The invention solves the problem of sealing failure caused by pre-static load and dynamic disturbance in a triaxial Hopkinson pressure bar experiment, thereby improving the success rate of the triaxial Hopkinson pressure bar experiment.
Description
Technical Field
The invention belongs to the field of rock mechanics, and relates to a rock sample sealing device and method in a triaxial Hopkinson pressure bar experiment.
Background
With the rapid development of engineering construction in the geotechnical field, various projects such as mine, water conservancy, energy and national defense construction go deep into the ground. The underground rock body is in a triaxial prestressed state under the coupling action of the self-weight stress and the tectonic stress; the underground rock mass is always subjected to dynamic disturbance due to high loading rate dynamic loads such as engineering blasting, earthquake and the like. In underground rock engineering, mechanical properties such as dynamic strength and deformation of rock mass in an engineering region have great significance on engineering construction safety and construction efficiency, and numerous scholars at home and abroad develop a great deal of research work on the dynamic rock breaking characteristics in a triaxial stress state based on a triaxial Hopkinson pressure bar experimental device. The sample sealing is the most basic condition for carrying out experiments, and most of the existing researches adopt a simple coating sealing method, so that the effect is poor, the breakdown is easy, the experiment failure is caused, and the dynamic response of the rock under the triaxial prestress condition is difficult to effectively research and describe.
Disclosure of Invention
The invention aims to provide a rock sample sealing method and a rock sample sealing device for a triaxial Hopkinson pressure bar experiment, so as to solve the problem of sealing failure caused by pre-static load and dynamic disturbance in the triaxial Hopkinson pressure bar experiment, thereby improving the success rate of the triaxial Hopkinson pressure bar experiment
The invention provides a device and a method for sealing a rock sample for a triaxial Hopkinson pressure bar experiment, which are mainly used for sealing a rock pattern arranged on a triaxial Hopkinson pressure bar experiment rock testing machine by adopting a shrinkage sealing washer, a heat shrinkage pipe and a shrinkage hoop.
Further, the method comprises the steps of:
(1) respectively sleeving shrinkage sealing gaskets on the near-rock sample ends of the transmission rod and the incident rod of the Hopkinson pressure bar;
(2) placing a rock sample between a transmission rod and an incident rod on a triaxial Hopkinson pressure bar experiment rock testing machine, and adhering the sample to the end faces of the transmission rod and the incident rod;
(3) sleeving a rock sample, a transmission rod and an incidence rod with a heat-shrinkable tube (the heat-shrinkable tube can be sleeved on the transmission rod or the incidence rod in advance, and after the sealing gasket is sleeved, the position of the heat-shrinkable tube is moved), so that the parts of the transmission rod and the incidence rod, which are sleeved with a shrinkage sealing washer, and the rock sample are completely coated by the heat-shrinkable tube;
(4) sleeving a contraction throat hoop on the surface of the heat-shrinkable tube at a position corresponding to the contraction sealing gasket and tightening;
(5) and coating hot melt adhesive at the junctions of the two pipe orifices of the heat shrinkable pipe and the transmission rod and the incident rod, and sealing the two pipe orifices of the heat shrinkable pipe.
Furthermore, the telescopic throat hoop is sleeved with a cylindrical filter screen, and the sleeving range of the cylindrical filter screen is larger than the covering range of the heat shrink tube, so that rock debris which possibly appears can be collected, and hydraulic oil is prevented from being polluted. In order to successfully sleeve, the filter screen can be sleeved on the transmission rod or the incidence rod in advance, and the position of the filter screen is moved to be coated in the last step after sealing.
Furthermore, the number of the contraction sealing gaskets and the contraction throat hoops is 2-4, and the contraction sealing gaskets and the contraction throat hoops are symmetrically assembled at the ends of the transmission rod and the incidence rod.
Further, the heating in the step (4) is heating by using a heat gun.
Furthermore, the inner diameter of the sealing washer is slightly smaller than the diameter of the rod, the sealing washer is firstly expanded to enable the inner diameter to exceed the diameter of the rod, and after the sealing washer is sleeved into a specified position, the sealing washer is contracted to be tightly contacted with the rod surface by utilizing the contractibility of the sealing washer. Preferably, the sealing gasket has a thickness of about 2-3mm and a width of about 5 mm.
Further, the heat shrinkable tube is a transparent polyolefin cylinder, and is heated to 80-120 ℃ by a heat gun for heat shrinkage.
Further, the length of the heat shrinkable tube is such that two tube openings thereof exceed two shrinkage sealing gaskets farthest from both ends of the rock pattern by more than 10 mm.
Furthermore, the contraction hose clamp is made of 304 stainless steel hose clamp with a handle, and the size of the hose clamp is adjusted by the handle, so that the hose clamp is convenient to install quickly.
Furthermore, the hot melt adhesive is an ethylene-vinyl acetate copolymer (EVA) adhesive rod.
Further, the filter screen is a 304 standard 201 stainless steel rust-proof ultra-fine thickening filter screen which only allows hydraulic oil to pass through.
The invention also provides a triaxial Hopkinson pressure bar experiment rock sample sealing device, which comprises a plurality of shrinkage sealing gaskets, a heat-shrinkable tube, a plurality of shrinkage hoops and a stainless steel filter screen, the contracted sealing washers are symmetrically sleeved on a transmission rod and an incidence rod of the triaxial Hopkinson pressure bar experiment rock testing machine at a certain distance, preferably 2-4 sealing washers are respectively sleeved on each rod, the heat-shrinkable tube is sleeved on the rock sample, the sealing washer, the transmission rod and the incident rod after being subjected to heat shrinkage, the transmission rod and the incident rod are completely coated with the parts of the transmission rod and the incident rod which are sleeved with the shrinkable sealing washer, and the whole rock sample, the contraction throat hoops and the sealing washers are sleeved and tightened in a one-to-one correspondence manner, the pipe orifices of the heat-shrinkable pipes are sealed on the transmission rod and the incident rod through sealing glue, the stainless steel filter screen is cylindrical and is sleeved outside the heat shrink tube and the shrink throat hoop, and the coverage range is larger than that of the heat shrink tube.
Compared with the prior art, the invention has the following beneficial effects:
1. the method has the advantages that the sealing process is easy to operate, the assembly and disassembly are simple, the sealing method with multiple layers (the heat-shrinkable tube, the hot melt adhesive, the shrinkable throat hoop and the filter screen are sealed with multiple layers) is adopted, the sealing effectiveness is ensured, the sealing effect can be effectively achieved, and the success rate of experiments is improved.
2. The method adopts the hot melt adhesive to seal the thermal shrinkage pipe interface, and cannot be punctured in the experimental process.
3. The method of the invention adopts the transparent heat shrinkable tube to observe the condition of the internal sample in the sealing process.
4. According to the method, the filter screen is adopted to cover the surface of the whole device, rock debris penetrating through the heat shrinkable tube can be collected, hydraulic oil is prevented from being polluted, and the sealing effect is guaranteed in the experimental process.
Drawings
FIG. 1 is a schematic view of the rock pattern and the location of the sealing gasket in the method of the invention;
FIG. 2 is a schematic view of a heat shrinkable tube set according to the method of the present invention;
FIG. 3 is a schematic diagram of a nested filter screen according to the method of the present invention;
FIG. 4 is a schematic illustration of the sealing step of the method of the present invention;
FIG. 5 is a graph showing the time course of ambient pressure under different conditions (including 7MPa, 14MPa, 21MPa and 28 MPa);
FIG. 6 shows the trend of the confining pressure during the dynamic loading process.
In the figure:
1 is a Hopkinson pressure bar, 1-1 is an incident bar, and 1-2 is a transmission bar;
2 is a rock sample;
3 is a contraction sealing washer, 3-1 to 3-6 correspond to 6 contraction sealing washers respectively;
4 is a cylindrical heat-shrinkable tube;
5 is a contraction throat hoop, 5-1 to 5-6 are respectively corresponding to 6 contraction throat hoops;
6 is hot melt adhesive, 6-1 and 6-2 respectively represent that the hot melt adhesive is coated on the ends of the transmission rod and the transmission rod;
and 7 is a cylindrical filter screen.
Detailed Description
The method according to the invention is further illustrated below with reference to specific examples and the accompanying drawings.
In the following embodiments, the shrinking sealing washer is a rubber ring, the diameter of which is slightly smaller than that of the projecting rod and the incident rod, and the shrinking sealing washer is tightly sleeved on the rod by virtue of the elastic shrinkage capacity of the shrinking sealing washer after being sleeved on the rod. The cylindrical heat-shrinkable tube, the shrinking hose clamp and the hot melt adhesive can be purchased in the market, and the cylindrical filter screen can be directly purchased or customized.
Examples
A rock sample sealing method for a triaxial Hopkinson pressure bar experiment mainly relates to materials shown in figures 1-3, and comprises the following steps: 6 shrink seal washers, a cylinder heat shrink tube, 6 shrink hose clamps, a hot melt adhesive and a cylinder filter screen.
The sealing process is mainly divided into the following 6 steps:
1) referring to fig. 2(1), a cylindrical heat-shrinkable tube 4 is sleeved on an incident rod 1-1, the distance of more than 50mm is reserved at the end part for sleeving a shrink sealing gasket, a filter screen 7 is sleeved on a transmission rod 1-2, the distance of more than 50mm is also reserved at the end part for sleeving the shrink sealing gasket, and then a sample is clamped between the incident rod 1-1 and the transmission rod 1-2;
2) as shown in fig. 4 (1), shrink seal gaskets 3-1 to 3-6 are sleeved on a Hopkinson pressure bar 1 at intervals of 5 to 8mm, and 3 shrink seal gaskets are respectively sleeved on an incident bar 1-1 and a transmission bar 1-2;
3) as shown in fig. 4 (2), a cylindrical heat-shrinkable tube 4 is sleeved on the surfaces of the 6 shrinkage sealing gaskets, two ends of the cylindrical heat-shrinkable tube respectively exceed the shrinkage sealing gasket 3-1 and the shrinkage sealing gasket by more than 3-65 mm, and the cylindrical heat-shrinkable tube is heated and heat-shrunk by a heat gun, so that the cylindrical heat-shrinkable tube is contacted with the sealing gaskets 3-1 to 3-6, the incident rod 1-1 and the transmission rod 1-2;
4) referring to FIG. 4 (3), the shrinking throat hoops 5-1 to 5-6 are sleeved on the surface of the cylindrical heat-shrinkable tube, aligned with the shrinking sealing gaskets 3-1 to 3-6 respectively, and tightened by a self-contained wrench, so that the heat-shrinkable tube 4, the shrinking sealing gaskets 3-1 to 3-6, the incident rod 1-1 and the transmission rod 1-2 are in close contact;
5) as shown in fig. 4 (4), the hot melt adhesive 6 is melted by heating, and is uniformly coated on both ends of the heat shrinkable tube, the coating thickness exceeds 3mm, the width exceeds 15mm (exceeds 10mm above both ends of the heat shrinkable tube), and does not contact with the shrinking throat hoops 5-1 and 5-6;
6) referring to FIG. 4 (5), after the hot melt adhesive is air-dried for more than 1 minute, the cylindrical filter screen 7 is sleeved on the surface of the device, and the length of the cylindrical filter screen exceeds 6-1 mm and 6-25 mm of the hot melt adhesive, so that the rock debris can not break through the heat-shrinkable tube and pollute the hydraulic oil.
The sealing effect of the method of the invention is verified as follows:
the experiment was performed according to the conventional procedure of the triaxial hopkinson pressure bar experiment. The confining pressure is slowly applied through a stable oil pressure system at a speed of 0.05MPa/s, and the change process of the confining pressure with time under different working conditions (including confining pressures of 7MPa, 14MPa, 21MPa and 28MPa) is obtained, as shown in FIG. 5. The trend of the confining pressure change during the dynamic load action is shown in fig. 6. The confining pressure applying process is stable (if the sealing is not good, the confining pressure loading is not good or the midway variation can occur), the confining pressure is almost constant in the dynamic load loading process, the sealing effect of the device in the whole process is good, and the sealing device is continuously effective, so that the success rate of the triaxial Hopkinson pressure bar experiment is improved.
Claims (3)
1. A triaxial Hopkinson pressure bar experiment rock sample sealing method is characterized in that a rock sample installed on a triaxial Hopkinson pressure bar experiment rock testing machine is sealed by adopting a shrinkage sealing washer, a heat shrinkage pipe and a shrinkage hoop, and comprises the following steps:
(1) 2-4 shrinkage sealing gaskets are respectively sleeved at the near-rock sample ends of a transmission rod and an incident rod of the Hopkinson pressure bar, and the inner diameters of the sealing gaskets are made of elastic rubber materials matched with the rod diameters of the transmission rod and the incident rod;
(2) placing a rock sample between a transmission rod and an incident rod on a triaxial Hopkinson pressure bar experiment rock testing machine, and adhering the sample with the end faces of the transmission rod and the incident rod by using a lubricant;
(3) sleeving a rock sample, a transmission rod and an incidence rod with heat-shrinkable tubes, so that the transmission rod and the incidence rod are sleeved with parts of shrinkage sealing gaskets, and the rock sample is completely coated by the heat-shrinkable tubes, wherein the length of the heat-shrinkable tubes is more than 10mm when two tube ports of the heat-shrinkable tubes exceed two shrinkage sealing gaskets farthest away from two ends of the rock sample, and the heat-shrinkable tubes are cylinders made of transparent polyolefin materials; heating the heat-shrinkable tube to 80-120 ℃ by using a heat gun to ensure that the heat-shrinkable tube is tightly attached to the rock sample, the surface of the transmission rod, the surface of the incident rod and the shrinkage sealing washer;
(4) sleeving and tightening a contraction throat hoop on the surface of the heat-shrinkable tube at a position corresponding to the contraction sealing gasket, wherein the number of the contraction sealing gasket and the contraction throat hoop is 2-4, and the contraction sealing gasket and the contraction throat hoop are symmetrically assembled at the end parts of the transmission rod and the incident rod; sleeving a cylindrical filter screen after sleeving the shrinkage throat hoop, wherein the sleeving range of the cylindrical filter screen is larger than the coverage range of the heat shrinkage pipe;
(5) and coating hot melt adhesive at the junctions of the two pipe orifices of the heat shrinkable pipe and the transmission rod and the incident rod, and sealing the two pipe orifices of the heat shrinkable pipe.
2. The method of claim 1, wherein the constriction throat band is a 304 stainless steel throat band with a handle.
3. The utility model provides a triaxial hopkinson pressure bar experiment rock sample sealing device, its characterized in that includes a plurality of shrink seal ring, pyrocondensation pipe, a plurality of shrink larynx hoop and stainless steel filter screen, shrink seal ring interval certain distance suit is on the transmission pole and the incident pole of triaxial hopkinson pressure bar experiment rock testing machine symmetrically, the pyrocondensation pipe overlaps on rock sample, seal ring, transmission pole, incident pole after the pyrocondensation, and complete cladding transmission pole, incident pole cover are equipped with the position of shrink seal ring to and whole rock sample, shrink larynx hoop and seal ring one-to-one suit tighten up, the pyrocondensation pipe mouth of pipe seals on transmission pole and incident pole through sealed glue, the stainless steel filter screen is the cylinder, and the suit is outside pyrocondensation pipe and shrink larynx hoop, and the coverage is greater than pyrocondensation pipe coverage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910220522.5A CN110095332B (en) | 2019-03-22 | 2019-03-22 | Sealing method and sealing device for rock sample in triaxial Hopkinson pressure bar experiment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910220522.5A CN110095332B (en) | 2019-03-22 | 2019-03-22 | Sealing method and sealing device for rock sample in triaxial Hopkinson pressure bar experiment |
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| Publication Number | Publication Date |
|---|---|
| CN110095332A CN110095332A (en) | 2019-08-06 |
| CN110095332B true CN110095332B (en) | 2020-11-17 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201910220522.5A Expired - Fee Related CN110095332B (en) | 2019-03-22 | 2019-03-22 | Sealing method and sealing device for rock sample in triaxial Hopkinson pressure bar experiment |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112014245B (en) * | 2020-08-13 | 2023-06-30 | 中国人民解放军空军工程大学 | Hopkinson pressure bar device for high-water-pressure rock breaking test and using method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103454164A (en) * | 2013-09-13 | 2013-12-18 | 安徽理工大学 | Multi-field coupled coal rock impact loading experimental device and method |
| CN103994716A (en) * | 2014-05-30 | 2014-08-20 | 东北大学 | Distributed rock deformation measuring method |
| CN108303310A (en) * | 2018-02-07 | 2018-07-20 | 成都理工大学 | Rock ordinary triaxial test test specimen sealing device and its application method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105092385B (en) * | 2015-08-06 | 2018-01-26 | 山东科技大学 | A kind of rock sample high-pressure water seal device and application method |
| CN107741364A (en) * | 2017-10-23 | 2018-02-27 | 中国矿业大学 | A kind of cuboid rock sample actual triaxial testing apparatus and method |
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2019
- 2019-03-22 CN CN201910220522.5A patent/CN110095332B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103454164A (en) * | 2013-09-13 | 2013-12-18 | 安徽理工大学 | Multi-field coupled coal rock impact loading experimental device and method |
| CN103994716A (en) * | 2014-05-30 | 2014-08-20 | 东北大学 | Distributed rock deformation measuring method |
| CN108303310A (en) * | 2018-02-07 | 2018-07-20 | 成都理工大学 | Rock ordinary triaxial test test specimen sealing device and its application method |
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| CN110095332A (en) | 2019-08-06 |
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